A secondary battery includes a power generating element, and the power generating element includes a positive electrode plate, in which a positive electrode active material layer is disposed on at least one surface of a first current collector, and a negative electrode plate, in which a negative electrode active material layer having an area larger than an area of the positive electrode active material layer is disposed on at least one surface of a second current collector. The positive electrode plate and the negative electrode plate are stacked with a separator interposed therebetween in a state in which the positive electrode active material layer and the negative electrode active material layer face each other (see Japanese Patent Application JP 2013-187021 A). The negative electrode plate includes a facing portion facing the positive electrode active material layer with the separator interposed therebetween and a non-facing portion positioned at the outer periphery of the facing portion and not facing the positive electrode active material layer with the separator interposed therebetween.
The power generation capacity of the battery having the above-described configuration is changed according to the facing area between the positive electrode active material layer and the negative electrode active material layer. If the area of the positive electrode active material layer and the area of the negative electrode active material layer are the same, the facing area between the positive electrode active material layer and the negative electrode active material layer can be changed by a relative positional shift of the positive electrode active material layer and the negative electrode active material layer in a direction intersecting with a stacking direction. Therefore, the negative electrode active material layer has the area larger than the area of the positive electrode active material layer so as to keep the facing area between the positive electrode active material layer and the negative electrode active material layer constant and suppress the change in the power generation capacity even when the positive electrode active material layer and the negative electrode active material layer are relatively misaligned.